1. Field of the Invention
The present invention relates generally to a method of extracting translations from translated texts, and more particularly, to a method of extracting translations from translated texts using sub-sentential alignment based on punctuations.
2. Background of the Invention
In an environment in which a source document and a translated document of the source document are compared, a number of applications may require alignment of sentences in the source document with those in the translated document. Examples of the applications include machine translation, computer-assisted language learning, and computer-assisted translation. Alignment on a sentence level is known to be useful for the extraction of bilingual and multilingual lexical and terminological information from existing bilingual and multilingual documents. As such, the ability to align sentences of the source and translated documents is important.
A number of sentence alignment techniques are known in the art, all of which focus on the sentence length or the lexical information of the documents. Under one sentence alignment technique, alignment is based on the length of the sentence, and the other available information is ignored. Therefore, the algorithm to implement this sentence alignment technique is simple and straightforward, and is adequate for two languages having similar characteristics (such as English and French). However, for two languages having very different characteristics, such as English and Chinese, the accuracy of sentence alignment is greatly decreased. Furthermore, the sentence alignment technique utilizes a relative simple dynamic programming technique. That is, the required memory capacity is dependent upon the length of the documents to be compared. Thus, the larger the pair of documents, the lesser the processing efficiency.
Another sentence alignment approach utilizes lexical information to compensate for the disadvantages of the aforementioned length-based approach. In it, individual sentences are split into words and the lexical information is extracted from the sentences to be aligned. To compensate for its reliability, this approach must rely heavily on external sources, such as dictionaries, to assure the accuracy of the translation. Therefore it is time-consuming. Accordingly, the efficiency of this approach is considerably lower.